Help! Z10 is stuck, won't finish startup or connect to PC

my z10 stl100-1 started to be slow in its start up few weeks ago then once i was restarting it and it fails to start up it remains stuck on the rounded bb logo till the battery drains and it shuts off
few hours ago i was trying an os reload to get it back alive again, but unfortunately its not syncing with bb link on my pc or bb desktop sw to reload the os, can anyone help me to know what i have to do to reload the os? and why the pc is unable to detect the device..
i need to know and i hope you'll answer me quickly bcz i need my phone working in the shortest time
thanks